Resonant converter

Abstract

A resonant converter is provided. The resonant converter includes a primary circuit, a secondary circuit, and a controller. The controller is configured to control a first primary switch and a first secondary switch by a first control signal, to control a second primary switch and a second secondary switch by a second control signal, to control a third primary switch and a third secondary switch by a third control signal, to control a fourth primary switch and a fourth secondary switch by a fourth control signal, to control a fifth primary switch and a fifth secondary switch by a fifth control signal, and to control a sixth primary switch and a sixth secondary switch by a sixth control signal.

Description

Technical Field

[0001] This case concerns a converter, specifically a resonant converter. Background Technology

[0002] With the rapid development of information technology, especially in cloud computing, big data, and artificial intelligence, the power consumption of data centers has increased significantly, and the power rating and power density of each power supply unit have also increased substantially. Three-phase resonant converters, due to their ability to reduce root mean square (RMS) current and peak current, and to enhance magnetic integration and power density, have become one of the best choices for data center applications.

[0003] However, the secondary circuit of the three-phase resonant converter has the disadvantages of current waveform distortion, difficulty in predicting current waveform under different switching frequencies and load conditions, and difficulty in controlling the synchronous rectifier during rapid load transients.

[0004] To overcome the shortcomings of existing technologies, it is necessary to provide a resonant converter. Summary of the Invention

[0005] This embodiment provides a resonant converter. A first control signal controls a first primary switch and a second secondary switch. A second control signal controls a second primary switch and a second secondary switch. A third control signal controls a third primary switch and a third secondary switch. A fourth control signal controls a fourth primary switch and a fourth secondary switch. A fifth control signal controls a fifth primary switch and a fifth secondary switch. A sixth control signal controls a sixth primary switch and a sixth secondary switch. In other words, the primary switches of the primary circuit and their corresponding secondary switches are controlled by substantially the same or identical control signals. In one embodiment, the primary switches of the primary circuit and their corresponding secondary switches are controlled by substantially the same control signal within a predetermined tolerance range. Therefore, the secondary circuit of the resonant converter has the advantages of smooth current waveforms, easy prediction of current waveforms under different switching frequencies and load conditions, and easy control of other components during rapid load transients.

[0006] According to one aspect of this case, a resonant converter is provided. The resonant converter includes a primary circuit, a secondary circuit, and a controller. The primary circuit includes a first bridge arm, a second bridge arm, and a third bridge arm. The first bridge arm includes a first primary switch and a second primary switch. The second bridge arm includes a third primary switch and a fourth primary switch. The third bridge arm includes a fifth primary switch and a sixth primary switch. The secondary circuit includes a first sub-circuit, a second sub-circuit, and a third sub-circuit. The first sub-circuit includes at least one first primary switch and at least one second secondary switch. The second sub-circuit includes at least one third secondary switch and at least one fourth secondary switch. The third sub-circuit includes at least one fifth secondary switch and at least one sixth secondary switch. The controller architecture controls the first primary switch and at least one first secondary switch via a first control signal, controls the second primary switch and at least one second secondary switch via a second control signal, controls the third primary switch and at least one third secondary switch via a third control signal, controls the fourth primary switch and at least one fourth secondary switch via a fourth control signal, controls the fifth primary switch and at least one fifth secondary switch via a fifth control signal, and controls the sixth primary switch and at least one sixth secondary switch via a sixth control signal.

[0007] Those skilled in the art will readily understand the above content of this case by referring to the following detailed description and accompanying drawings. Attached Figure Description

[0008] Figure 1 This is a circuit diagram of the circuit topology of the resonant converter in the first embodiment of this case.

[0009] Figure 2A for Figure 1 A timing waveform diagram of the control signal of the controller of the resonant converter in the first embodiment.

[0010] Figure 2B for Figure 1 A timing waveform diagram of the control signal of the controller of the resonant converter in a second embodiment.

[0011] Figure 3A for Figure 1 The diagram shows the parameter waveforms of the first and second control signals and the timing waveforms of the current for the resonant converter under operating cycle of 17% and light load conditions.

[0012] Figure 3B for Figure 1 The diagram shows the parameter waveforms of the first and second control signals and the timing waveforms of the current for the resonant converter under operating cycle conditions of 33% and light load.

[0013] Figure 3C for Figure 1The diagram shows the parameter waveforms of the first and second control signals and the timing waveforms of the current in the resonant converter under operating cycle of 17% and heavy load conditions.

[0014] Figure 3D for Figure 1 The diagram shows the parameter waveforms of the first and second control signals and the timing waveforms of the current for the resonant converter under operating cycle conditions of 33% and heavy load.

[0015] Figure 4 Show Figure 1 The relative relationship between the duty cycle and switching frequency of the resonant converter.

[0016] Figure 5 Show Figure 1 The relative relationship between the output voltage, duty cycle, and switching frequency of the resonant converter.

[0017] Figure 6 This is a circuit diagram of the circuit topology of the resonant converter in the second embodiment of this case.

[0018] List of reference numerals

[0019] 1, 1a: Resonant converter

[0020] 2: Primary Circuit

[0021] 21: First bridge arm

[0022] 22: Second bridge arm

[0023] 23: Third bridge arm

[0024] 3: Resonant circuit components

[0025] 31: First resonant circuit

[0026] 32: Second resonant circuit

[0027] 33: Third resonant circuit

[0028] 4: Secondary circuit

[0029] 41: First Sub-circuit

[0030] 42: Second Sub-circuit

[0031] 43: Third Sub-circuit

[0032] 5: Controller

[0033] 51: Subtractor

[0034] 52: Error Amplifier

[0035] 53: Modulator

[0036] 54: Driver

[0037] Sa1: First primary switch

[0038] Sa1': Second primary switch

[0039] Sb1: Third primary switch

[0040] Sb1': Fourth primary switch

[0041] Sc1: Fifth primary switch

[0042] Sc1': Sixth primary switch

[0043] Sa2, Sa3: Primary switches

[0044] Sa2', Sa3': Secondary stage switches

[0045] Sb2, Sb3: Third-stage switches

[0046] Sb2', Sb3': Fourth secondary switch

[0047] Sc2, Sc3: Fifth secondary switches

[0048] Sc2', Sc3': Sixth secondary switch

[0049] A1: First midpoint

[0050] B1: Second Midpoint

[0051] C1: Third midpoint

[0052] A2, A2': First sub-midpoint

[0053] A3, B2': Midpoint of the second sub-point

[0054] B2, C2': Midpoint of the third sub-point

[0055] B3: Midpoint of the fourth sub-point

[0056] C2: Midpoint of the fifth sub-point

[0057] C3: Midpoint of the sixth sub-point

[0058] Cra: First resonant capacitor

[0059] Crb: Second resonant capacitor

[0060] Crc: Third resonant capacitor

[0061] Lra: First resonant inductor

[0062] Lrb: Second resonant inductor

[0063] Lrc: Third resonant inductor

[0064] Lma: First magnetized inductor

[0065] Lmb: Second magnetizing inductor

[0066] Lmc: Third magnetizing inductor

[0067] Ta: First Transformer

[0068] Tb: Second Transformer

[0069] Tc: Third Transformer

[0070] Ra1: First resonant resistor

[0071] Rb1: Second resonant resistor

[0072] Rc1: Third resonant resistor

[0073] Ra2: Fourth resonant resistor

[0074] Rb2: Fifth resonant resistor

[0075] Rc2: Sixth resonant resistor

[0076] Sa: First control signal

[0077] Sa': Second control signal

[0078] Sb: Third control signal

[0079] Sb': Fourth control signal

[0080] Sc: Fifth control signal

[0081] Sc': Sixth control signal

[0082] Vo: Output voltage

[0083] Voref: Reference voltage

[0084] Ira, Isa, Ima: Electric current

[0085] fsw: Switching frequency Detailed Implementation

[0086] The present invention will now be described in more detail with reference to the following embodiments. It should be noted that the description of the following preferred embodiments provided herein is for illustrative purposes only and is not intended to be exhaustive or to limit the present invention to the precise form disclosed.

[0087] Figure 1This is a circuit diagram of the circuit topology of the resonant converter in the first embodiment of this case. Figure 2A for Figure 1 A timing waveform diagram of the control signal of the controller for the resonant converter in a first embodiment. (See diagram for example.) Figure 1 As shown, the resonant converter 1 in this embodiment includes a three-phase resonant converter, which includes a primary circuit 2, a resonant circuit assembly 3, a secondary circuit 4, and a controller 5. The primary circuit 2 includes a first bridge arm 21, a second bridge arm 22, and a third bridge arm 23. The first bridge arm 21 includes a first primary switch Sa1 and a second primary switch Sa1'. A first midpoint A1 is formed between the first primary switch Sa1 and the second primary switch Sa1'. The second bridge arm 22 includes a third primary switch Sb1 and a fourth primary switch Sb1'. A second midpoint B1 is formed between the third primary switch Sb1 and the fourth primary switch Sb1'. The third bridge arm 23 includes a fifth primary switch Sc1 and a sixth primary switch Sc1'. A third midpoint C1 is formed between the fifth primary switch Sc1 and the sixth primary switch Sc1'.

[0088] The resonant circuit assembly 3 includes a first resonant circuit 31, a second resonant circuit 32, and a third resonant circuit 33. The first resonant circuit 31 includes a first resonant capacitor Cra, a first resonant inductor Lra, a first magnetizing inductor Lma, and a first transformer Ta. The first transformer Ta includes a first primary winding and a second primary winding. The first resonant capacitor Cra is connected between a first midpoint A1 and a first terminal of the first primary winding of the first transformer Ta. The first resonant capacitor Cra is connected to the terminal at the first midpoint A1, forming the first input terminal of the first resonant circuit 31. The first magnetizing inductor Lma is connected in parallel with the first primary winding of the first transformer Ta. The first terminal of the first resonant inductor Lra is connected to the second terminal of the first primary winding of the first transformer Ta. The second resonant circuit 32 includes a second resonant capacitor Creb, a second resonant inductor Lrb, a second magnetizing inductor Lmb, and a second transformer Tb. The second transformer Tb includes a second primary winding and a second secondary winding. The second resonant capacitor Creb is connected between a second midpoint B1 and a first terminal of the second primary winding of the second transformer Tb. The second resonant capacitor Crb is connected to the endpoint of the second midpoint B1, forming the first input terminal of the second resonant circuit 32. The second magnetizing inductor Lmb is connected in parallel with the second primary winding of the second transformer Tb. The first terminal of the second resonant inductor Lrb is connected to the second terminal of the second primary winding of the second transformer Tb. The third resonant circuit 33 includes a third resonant capacitor Crc, a third resonant inductor Lrc, a third magnetizing inductor Lmc, and a third transformer Tc. The third transformer Tc includes a third primary winding and a third secondary winding. The third resonant capacitor Crc is connected between the third midpoint C1 and the first terminal of the third primary winding of the third transformer Tc. The third resonant capacitor Crc is connected to the endpoint of the third midpoint C1, forming the first input terminal of the third resonant circuit 33. The third magnetizing inductor Lmc is connected in parallel with the third primary winding of the third transformer Tc. The first terminal of the third resonant inductor Lrc ​​is connected to the second terminal of the third primary winding of the third transformer Tc. The second end of the first resonant inductor Lra forms the second input terminal of the first resonant circuit 31, the second end of the second resonant inductor Lrb forms the second input terminal of the second resonant circuit 32, and the second end of the third resonant inductor Lrc ​​forms the second input terminal of the third resonant circuit 33. The second ends of the first resonant inductor Lra, the second resonant inductor Lrb, and the third resonant inductor Lrc ​​are connected to each other.

[0089] Secondary circuit 4 includes a first sub-circuit 41, a second sub-circuit 42, and a third sub-circuit 43 connected in parallel. The first sub-circuit 41 includes two primary switches Sa2 and Sa3, and two secondary switches Sa2' and Sa3'. The primary and secondary switches Sa2' are sequentially connected to form a first sub-midpoint A2. The first sub-midpoint A2 is connected to one end of the primary winding of the first transformer Ta. The secondary and primary switches Sa3' are sequentially connected to form a second sub-midpoint A3. The second sub-midpoint A3 is connected to the other end of the primary winding of the first transformer Ta. Secondary circuit 42 includes two tertiary switches Sb2 and Sb3, and two quaternary switches Sb2' and Sb3'. The tertiary and quaternary switches Sb2' are sequentially connected to form a third sub-midpoint B2. The third sub-midpoint B2 is connected to one end of the secondary winding of the second transformer Tb. The fourth secondary switch Sb3' and the third secondary switch Sb3 are sequentially connected to form the fourth sub-midpoint B3. The fourth sub-midpoint B3 is connected to the other end of the second secondary winding of the second transformer Tb. The third sub-circuit 43 includes two fifth secondary switches Sc2 and Sc3 and two sixth secondary switches Sc2' and Sc3'. The fifth secondary switch Sc2 and the sixth secondary switch Sc2' are sequentially connected to form the fifth sub-midpoint C2. The fifth sub-midpoint C2 is connected to one end of the third secondary winding of the third transformer Tc. The sixth secondary switch Sc3' and the fifth secondary switch Sc3 are sequentially connected to form the sixth sub-midpoint C3. The sixth sub-midpoint C3 is connected to the other end of the third secondary winding of the third transformer Tc.

[0090] In some embodiments, each of the first sub-circuit 41, the second sub-circuit 42, and the third sub-circuit 43 includes one or more secondary switches.

[0091] The controller 5 architecture generates a first control signal Sa, a second control signal Sa', a third control signal Sb, a fourth control signal Sb', a fifth control signal Sc, and a sixth control signal Sc'. The first control signal Sa controls the first primary switch Sa1 and two primary secondary switches Sa2 and Sa3. The second control signal Sa' controls the second primary switch Sa1' and two secondary secondary switches Sa2' and Sa3'. The third control signal Sb controls the third primary switch Sb1 and two secondary secondary switches Sb2 and Sb3. The fourth control signal Sb' controls the fourth primary switch Sb1' and two secondary secondary switches Sb2' and Sb3'. The fifth control signal Sc controls the fifth primary switch Sc1 and two secondary secondary switches Sc2 and Sc3. The sixth control signal Sc' controls the sixth primary switch Sc1' and two secondary secondary switches Sc2' and Sc3'.

[0092] In this embodiment, as Figure 2A As shown, the working period of the first control signal Sa is approximately equal to the working period of the second control signal Sa'. The phase difference between the first control signal Sa and the second control signal Sa' is 180 degrees. The working period of the third control signal Sb is approximately equal to the working period of the fourth control signal Sb'. The phase difference between the third control signal Sb and the fourth control signal Sb' is 180 degrees. The working period of the fifth control signal Sc is approximately equal to the working period of the sixth control signal Sc'. The phase difference between the fifth control signal Sc and the sixth control signal Sc' is 180 degrees. The phase difference between the first control signal Sa and the third control signal Sb is 120 degrees. The phase difference between the first control signal Sa and the fifth control signal Sc is 240 degrees. The phase difference between the third control signal Sb and the fifth control signal Sc is 120 degrees. In this embodiment, the working periods of the first control signal Sa, the second control signal Sa', the third control signal Sb, the fourth control signal Sb', the fifth control signal Sc, and the sixth control signal Sc' are all less than 50%.

[0093] according to Figure 2A The waveforms are as follows: the first primary switch Sa1 and the two first-stage switches Sa2 and Sa3 have approximately the same duty cycle, switching frequency, and dead time. The second primary switch Sa1' and the two second-stage switches Sa2' and Sa3' have approximately the same duty cycle, switching frequency, and dead time. The third primary switch Sb1 and the two third-stage switches Sb2 and Sb3 have approximately the same duty cycle, switching frequency, and dead time. The fourth primary switch Sb1' and the two fourth-stage switches Sb2' and Sb3' have approximately the same duty cycle, switching frequency, and dead time. The fifth primary switch Sc1 and the two fifth-stage switches Sc2 and Sc3 have approximately the same duty cycle, switching frequency, and dead time. The sixth primary switch Sc1' and the two sixth-stage switches Sc2' and Sc3' have approximately the same duty cycle, switching frequency, and dead time.

[0094] In summary, the embodiments of this invention provide a resonant converter 1. A first control signal controls a first primary switch Sa1 and first secondary switches Sa2 and Sa3. A second control signal controls a second primary switch Sa1' and second secondary switches Sa2' and Sa3'. A third control signal controls a third primary switch Sb1 and third secondary switches Sb2 and Sb3. A fourth control signal controls a fourth primary switch Sb1' and fourth secondary switches Sb2' and Sb3'. A fifth control signal controls a fifth primary switch Sc1 and fifth secondary switches Sc2 and Sc3. A sixth control signal controls a sixth primary switch Sc1' and sixth secondary switches Sc2' and Sc3'. In other words, the primary switches of the primary circuit and their corresponding secondary switches of the secondary circuit can be controlled by the same control signal. Alternatively, in one embodiment, the primary switches of the primary circuit and their corresponding secondary switches of the secondary circuit are controlled by approximately the same control signal within a predetermined tolerance range. Therefore, the secondary circuit of the resonant converter has the advantages of smooth current waveform, easy prediction of current waveform under different switching frequencies and load conditions, and easy control of other components during rapid load transients.

[0095] In some embodiments, the primary and secondary switches may be controlled by logically related but not identical control signals.

[0096] Figure 2B for Figure 1 A timing waveform diagram of the control signal of the controller for the resonant converter in a second embodiment. Compared to Figure 2A The waveform, such as Figure 2B As shown, in this embodiment, the working period of the first control signal Sa, the working period of the second control signal Sa', the working period of the third control signal Sb, the working period of the fourth control signal Sb', the working period of the fifth control signal Sc, and the working period of the sixth control signal Sc' are each approximately equal to 50%.

[0097] Refer to Figure 1 In this embodiment, the controller 5 includes a subtractor 51, an error amplifier 52, a modulator 53, and a driver 54. The subtractor 51 is configured to receive the output voltage Vo and the reference voltage Voref of the resonant converter 1. The subtractor 51 is configured to subtract the output voltage Vo from the reference voltage Voref to output a voltage difference. The error amplifier 52 is configured to receive and compensate for the voltage difference to output a transient voltage. The modulator 53 is a voltage-frequency modulator or a voltage-duty cycle modulator. The modulator 53 is configured to modulate the transient voltage. The driver 54 is configured to generate a first control signal Sa, a second control signal Sa', a third control signal Sb, a fourth control signal Sb', a fifth control signal Sc, and a sixth control signal Sc' based on the transient voltage modulated by the modulator 53.

[0098] Figure 3A for Figure 1 The diagram illustrates the parameter waveforms of the first and second control signals and the timing waveforms of the current for a resonant converter operating at 17% of its operating cycle and under light load conditions. Figure 3A As shown, the first control signal Sa, the second control signal Sa', the current flowing through the first resonant circuit 31 (i.e., current Ira), and the current flowing through the first sub-circuit 41 (i.e., current Isa) are illustrated in sequence. In this embodiment, the operating period of the first control signal Sa and the second control signal Sa' is 17%, and the resonant converter 1 is under light load conditions. At time t1, the first resonant circuit 31 and the first sub-circuit 41 are turned on to achieve zero-current switching. The third control signal Sb and the fourth control signal Sb' are similar to the first control signal Sa and the second control signal Sa', respectively, and have a phase difference of 120 degrees. The fifth control signal Sc and the sixth control signal Sc' are similar to the first control signal Sa and the second control signal Sa', respectively, and have a phase difference of 240 degrees.

[0099] Figure 3B for Figure 1 The diagram illustrates the parameter waveforms of the first and second control signals and the timing waveforms of the current for a resonant converter operating at 33% of its cycle and under light load conditions. Figure 3B In this context, the current Ima represents the current flowing through the first magnetized inductor Lma. Similar to... Figure 3A ,like Figure 3B As shown, the operating cycles of the first control signal Sa and the second control signal Sa' are 33%, and the resonant converter 1 is under light load conditions. At time t1, the first resonant circuit 31 and the first sub-circuit 41 are turned on to achieve zero-current switching.

[0100] Figure 3C for Figure 1 The diagram illustrates the parameter waveforms of the first and second control signals and the timing waveforms of the current in a resonant converter operating at 17% duty cycle and under heavy load conditions. (Similar to...) Figure 3A ,like Figure 3C As shown, the operating cycles of the first control signal Sa and the second control signal Sa' are 17%, and the resonant converter 1 is under heavy load conditions. At time t1, the first resonant circuit 31 and the first sub-circuit 41 are turned on to achieve zero-current switching.

[0101] Figure 3D for Figure 1 The diagram illustrates the parameter waveforms of the first and second control signals and the timing waveforms of the current in a resonant converter operating at 33% duty cycle and under heavy load conditions. (Similar to...) Figure 3A ,like Figure 3DAs shown, the operating cycles of the first control signal Sa and the second control signal Sa' are 33%, and the resonant converter 1 is under heavy load conditions. At time t1, the first resonant circuit 31 and the first sub-circuit 41 are turned on to achieve zero-current switching.

[0102] Figure 4 Show Figure 1 The relative relationship between the duty cycle and switching frequency of the resonant converter. For example... Figure 4 As shown, the horizontal axis represents the operating period of the control signal, and the vertical axis represents the switching frequency of the corresponding switch. The operating area marked in the figure is the permissible operating area of ​​the resonant converter in this case. The switching frequency is between k1 times and k2 times the resonant frequency. k1 is greater than or approximately equal to 1.1. k2 is less than or approximately equal to 5. In other words, in one embodiment, the switching frequency is between 1.1 times and 5 times the resonant frequency. In one embodiment, when the switching frequency is approximately equal to the resonant frequency, the operating period of the control signal is between point Y and 0.5. Point Y is less than or approximately equal to 0.2. In other words, in one embodiment, the operating period of the control signal is between 0.2 and 0.5. In one embodiment, when the switching frequency is approximately equal to k2 times the resonant frequency, the operating period of the control signal is between 0.16 and point Z. Point Z is between 0.33 and 0.4. In other words, in one embodiment, the operating period of the control signal is between 0.16 and 0.4. At low duty cycles (e.g., less than 0.2), the switching frequency is typically higher than the resonant frequency to reduce circulating current. In this embodiment, the switching frequency is between k1 and k2 times the resonant frequency to reduce switching losses.

[0103] Figure 5 Show Figure 1 The relative relationship between the output voltage, duty cycle, and switching frequency of the resonant converter. For example... Figure 5 As shown, the Z-axis represents the output voltage Vo of resonant converter 1, the X-axis represents the duty cycle of the control signal, and the Y-axis represents the switching frequency fsw of the corresponding switch. When the switching frequency fsw increases, the output voltage Vo typically decreases. At a fixed frequency, the duty cycle initially increases from 0.1 to 0.5, the output voltage Vo increases, and eventually tends to level off or reach a flat region. In the specific region marked "high pulse current," the voltage drops sharply due to extremely high transient current spikes experienced in the switch. To avoid this problem, the specific region enclosed by the thick black line (i.e.,...) Figure 4 The operating region shown in the figure illustrates the optimal operating range of the resonant converter 1 in this embodiment.

[0104] Figure 6 This is a circuit diagram of the resonant converter circuit topology of the second embodiment of this case. The resonant converter 1a is connected to... Figure 1Compared to the resonant converter 1, in this embodiment, as... Figure 6 As shown, the first sub-circuit 41 is a bridge arm and includes a first-stage switch Sa2 and a second-stage switch Sa2'. The first-stage switch Sa2 and the second-stage switch Sa2' form a first sub-midpoint A2'. The second sub-circuit 42 is a bridge arm and includes a third-stage switch Sb2 and a fourth-stage switch Sb2'. The third-stage switch Sb2 and the fourth-stage switch Sb2' form a second sub-midpoint B2'. The third sub-circuit 43 is a bridge arm and includes a fifth-stage switch Sc2 and a sixth-stage switch Sc2'. The fifth-stage switch Sc2 and the sixth-stage switch Sc2' form a third sub-midpoint C2'.

[0105] The first resonant circuit 31 includes a first resonant resistor Ra1, a first transformer Ta, and a first magnetizing inductor Lma. The first resonant resistor Ra1 is connected between the first midpoint A1 and the first end of the first primary winding of the first transformer Ta. The first resonant resistor Ra1 connected to the end of the first midpoint A1 forms the first input terminal of the first resonant circuit 31. The first end of the first primary winding of the first transformer Ta forms the first output terminal of the first resonant circuit 31. The first end of the first primary winding of the first transformer Ta is connected to the first sub-midpoint A2'. The second resonant circuit 32 includes a second resonant resistor Rb1, a second transformer Tb, and a second magnetizing inductor Lmb. The second resonant resistor Rb1 is connected between the second midpoint B1 and the first end of the second primary winding of the second transformer Tb. The second resonant resistor Rb1 connected to the end of the second midpoint B1 forms the first input terminal of the second resonant circuit 32. The first end of the second secondary winding of the second transformer Tb forms the first output terminal of the second resonant circuit 32. The first end of the second secondary winding of the second transformer Tb is connected to the second sub-midpoint B2'. The third resonant circuit 33 includes a third resonant resistor Rc1, a third transformer Tc, and a third magnetizing inductor Lmc. The third resonant resistor Rc1 is connected between the third midpoint C1 and the first end of the third primary winding of the third transformer Tc. The terminal of the third resonant resistor Rc1 connected to the third midpoint C1 forms the first input terminal of the third resonant circuit 33. The first end of the third secondary winding of the third transformer Tc forms the first output terminal of the third resonant circuit 33. The first end of the third secondary winding of the third transformer Tc is connected to the third sub-midpoint C2'. The second end of the first primary winding of the first transformer Ta forms the second output terminal of the first resonant circuit 31, the second end of the second secondary winding of the second transformer Tb forms the second output terminal of the second resonant circuit 32, and the second end of the third secondary winding of the third transformer Tc forms the second output terminal of the third resonant circuit 33. The second ends of the first primary winding of the first transformer Ta, the second secondary winding of the second transformer Tb, and the third secondary winding of the third transformer Tc are connected to each other.

[0106] The resonant circuit assembly 3 includes a fourth resonant resistor Ra2, a fifth resonant resistor Rb2, and a sixth resonant resistor Rc2. The fourth resonant resistor Ra2 is connected between the second terminal of the second primary winding of the second transformer Tb and the second terminal of the third primary winding of the third transformer Tc. The fifth resonant resistor Rb2 is connected between the second terminal of the first primary winding of the first transformer Ta and the second terminal of the second primary winding of the second transformer Tb. The sixth resonant resistor Rc2 is connected between the second terminal of the first primary winding of the first transformer Ta and the second terminal of the third primary winding of the third transformer Tc. In other words, the second input terminals of the first resonant circuit 31, the second input terminal of the second resonant circuit 32, and the second input terminal of the third resonant circuit 33 are connected to each other in a delta configuration.

[0107] In summary, this embodiment provides a resonant converter. A first control signal controls a first primary switch and a second secondary switch. A second control signal controls a second primary switch and a second secondary switch. A third control signal controls a third primary switch and a third secondary switch. A fourth control signal controls a fourth primary switch and a fourth secondary switch. A fifth control signal controls a fifth primary switch and a fifth secondary switch. A sixth control signal controls a sixth primary switch and a sixth secondary switch. In other words, the primary switches of the primary circuit and their corresponding secondary switches are controlled by substantially the same or identical control signals. Alternatively, in some embodiments, the primary switches of the primary circuit and their corresponding secondary switches are controlled by substantially the same control signal within a predetermined tolerance range. Therefore, the secondary circuit of the resonant converter has the advantages of smooth current waveforms, easy prediction of current waveforms under different switching frequencies and load conditions, and easy control of other components during rapid load transients.

[0108] Although this application has been described above with reference to the most practical and preferred embodiments, it is not intended to limit the application to the disclosed embodiments. Rather, it is intended to cover various modifications and similar configurations included within the spirit and scope of the appended claims. This scope should be interpreted in the broadest sense to include all such modifications and similar structures.

Claims

1. A resonant converter, comprising: A primary circuit includes a first bridge arm, a second bridge arm, and a third bridge arm, wherein the first bridge arm includes a first primary switch and a second primary switch, the second bridge arm includes a third primary switch and a fourth primary switch, and the third bridge arm includes a fifth primary switch and a sixth primary switch. A primary circuit includes a first sub-circuit, a second sub-circuit, and a third sub-circuit. The first sub-circuit includes at least one primary switch and at least one secondary switch. The second sub-circuit includes at least one secondary switch and at least one fourth secondary switch. The third sub-circuit includes at least one fifth secondary switch and at least one sixth secondary switch. A controller is configured to control a first primary switch and at least one secondary switch via a first control signal, a second primary switch and at least one secondary switch via a second control signal, a third primary switch and at least one tertiary switch via a third control signal, a fourth primary switch and at least one fourth secondary switch via a fourth control signal, a fifth primary switch and at least one fifth secondary switch via a fifth control signal, and a sixth primary switch and at least one sixth secondary switch via a sixth control signal.

2. The resonant converter as claimed in claim 1, wherein, The working cycle of the first control signal is equal to the working cycle of the second control signal, and the phase difference between the first control signal and the second control signal is 180 degrees; the working cycle of the third control signal is equal to the working cycle of the fourth control signal, and the phase difference between the third control signal and the fourth control signal is 180 degrees; the working cycle of the fifth control signal is equal to the working cycle of the sixth control signal, and the phase difference between the fifth control signal and the sixth control signal is 180 degrees.

3. The resonant converter as claimed in claim 2, wherein the operating period of the first control signal, the operating period of the second control signal, the operating period of the third control signal, the operating period of the fourth control signal, the operating period of the fifth control signal, and the operating period of the sixth control signal are all 50%.

4. The resonant converter as claimed in claim 2, wherein the operating period of the first control signal, the operating period of the second control signal, the operating period of the third control signal, the operating period of the fourth control signal, the operating period of the fifth control signal, and the operating period of the sixth control signal are all less than 50%.

5. The resonant converter as claimed in claim 1, wherein the phase difference between the first control signal and the third control signal is 120 degrees, and the phase difference between the first control signal and the fifth control signal is 240 degrees.

6. The resonant converter of claim 1, wherein the first primary switch and the at least one secondary switch have the same operating period, switching frequency, and dead time; the second primary switch and the at least one secondary switch have the same operating period, switching frequency, and dead time; the third primary switch and the at least one third secondary switch have the same operating period, switching frequency, and dead time; the fourth primary switch and the at least one fourth secondary switch have the same operating period, switching frequency, and dead time; the fifth primary switch and the at least one fifth secondary switch have the same operating period, switching frequency, and dead time; and the sixth primary switch and the at least one sixth secondary switch have the same operating period, switching frequency, and dead time.

7. The resonant converter of claim 1, wherein a working period of the first control signal, a working period of the second control signal, a working period of the third control signal, a working period of the fourth control signal, a working period of the fifth control signal and / or a working period of the sixth control signal are between 0.2 and 0.5, or between 0.16 and 0.

4.

8. The resonant converter of claim 1, wherein all switching frequencies of the first primary switch, the second primary switch, the third primary switch, the fourth primary switch, the fifth primary switch, the sixth primary switch, the at least one first secondary switch, the at least one second secondary switch, the at least one third secondary switch, the at least one fourth secondary switch, the at least one fifth secondary switch, and the at least one sixth secondary switch are each between 1.1 times and 5 times a resonant frequency of the resonant converter.

9. The resonant converter of claim 1, wherein the controller comprises: A subtractor is configured to receive a reference voltage and an output voltage of the resonant converter, and to subtract the output voltage from the reference voltage to output a voltage difference. An error amplifier, configured to receive and compensate for the voltage difference to output a transient voltage; A modulator, with an architecture designed to modulate this transient voltage; as well as A driver, configured to generate the first control signal, the second control signal, the third control signal, the fourth control signal, the fifth control signal, and the sixth control signal based on the transient voltage modulated by the modulator.

10. The resonant converter of claim 1, wherein the resonant converter includes a resonant circuit assembly, the resonant circuit assembly including a first resonant circuit, a second resonant circuit and a third resonant circuit, the first resonant circuit being connected between the first bridge arm and the first sub-circuit, the second resonant circuit being connected between the second bridge arm and the second sub-circuit, and the third resonant circuit being connected between the third bridge arm and the third sub-circuit.

11. The resonant converter of claim 10, wherein a first midpoint is formed between the first primary switch and the second primary switch, a second midpoint is formed between the third primary switch and the fourth primary switch, and a third midpoint is formed between the fifth primary switch and the sixth primary switch, wherein the first sub-circuit includes two first-stage switches and two second-stage switches, one of the two first-stage switches is connected to one of the two second-stage switches to form a first sub-midpoint, and the other of the two first-stage switches is connected to the other of the two second-stage switches to form a second sub-midpoint. The second sub-circuit includes two third-level switches and two fourth-level switches. One of the two third-level switches is connected to one of the two fourth-level switches to form a third sub-midpoint, and the other of the two third-level switches is connected to the other of the two fourth-level switches to form a fourth sub-midpoint. The third sub-circuit also includes two fifth-level switches and two sixth-level switches. One of the two fifth-level switches is connected to one of the two sixth-level switches to form a fifth sub-midpoint, and the other of the two fifth-level switches is connected to the other of the two sixth-level switches to form a sixth sub-midpoint.

12. The resonant converter of claim 11, wherein a first input terminal of the first resonant circuit is connected to the first midpoint, a first output terminal of the first resonant circuit is connected to the first sub-midpoint, a second output terminal of the first resonant circuit is connected to the second sub-midpoint, a first input terminal of the second resonant circuit is connected to the second midpoint, a first output terminal of the second resonant circuit is connected to the third sub-midpoint, a second output terminal of the second resonant circuit is connected to the fourth sub-midpoint, a first input terminal of the third resonant circuit is connected to the third midpoint, a first output terminal of the third resonant circuit is connected to the fifth sub-midpoint, a second output terminal of the third resonant circuit is connected to the sixth sub-midpoint, and the second input terminals of the first resonant circuit, the second input terminals of the second resonant circuit, and the second input terminals of the third resonant circuit are connected to each other.

13. The resonant converter of claim 11, wherein the first resonant circuit includes a first resonant capacitor, a first resonant inductor, a first magnetizing inductor, and a first transformer, the first transformer including a first primary winding and a second secondary winding, the first resonant capacitor being connected between the first midpoint and a first end of the first primary winding, the first magnetizing inductor being connected in parallel with the first primary winding, a first end of the first resonant inductor being connected to a second end of the first primary winding, and the two ends of the first secondary winding being respectively connected to the first sub-midpoint and the second sub-midpoint; the second resonant circuit includes a second resonant capacitor, a second resonant inductor, a second magnetizing inductor, and a second transformer, the second transformer including a second primary winding and a second secondary winding, the second resonant capacitor being connected between the second midpoint and a first end of the second primary winding, and the... The second magnetizing inductor is connected in parallel with the second primary winding. A first end of the second resonant inductor is connected to a second end of the second primary winding. The two ends of the first primary winding are respectively connected to the third sub-midpoint and the fourth sub-midpoint. The third resonant circuit includes a third resonant capacitor, a third resonant inductor, a third magnetizing inductor, and a third transformer. The third transformer includes a third primary winding and a third secondary winding. The third resonant capacitor is connected between the third midpoint and a first end of the third primary winding. The third magnetizing inductor is connected in parallel with the third primary winding. A first end of the third resonant inductor is connected to a second end of the third primary winding. The two ends of the third secondary winding are respectively connected to the fifth sub-midpoint and the sixth sub-midpoint. The second ends of the first resonant inductor, the second resonant inductor, and the third resonant inductor are connected to each other.

14. The resonant converter of claim 10, wherein a first midpoint is formed between the first primary switch and the second primary switch, a second midpoint is formed between the third primary switch and the fourth primary switch, a third midpoint is formed between the fifth primary switch and the sixth primary switch, the first sub-circuit is a bridge arm and includes a first primary switch and a second secondary switch, a first sub-midpoint is formed between the first primary switch and the second secondary switch, the second sub-circuit is a bridge arm and includes a third secondary switch and a fourth secondary switch, a second sub-midpoint is formed between the third secondary switch and the fourth secondary switch, the third sub-circuit is a bridge arm and includes a fifth secondary switch and a sixth secondary switch, a third sub-midpoint is formed between the fifth secondary switch and the sixth secondary switch.

15. The resonant converter of claim 14, wherein a first input terminal of the first resonant circuit is connected to the first midpoint, a first output terminal of the first resonant circuit is connected to the first sub-midpoint, a first input terminal of the second resonant circuit is connected to the second midpoint, a first output terminal of the second resonant circuit is connected to the second sub-midpoint, a first input terminal of the third resonant circuit is connected to the third midpoint, a first output terminal of the third resonant circuit is connected to the third sub-midpoint, a second input terminal of the first resonant circuit, a second input terminal of the second resonant circuit, and a second input terminal of the third resonant circuit are connected to each other in a delta configuration, and a second output terminal of the first resonant circuit, a second output terminal of the second resonant circuit, and a second output terminal of the third resonant circuit are connected to each other.

16. The resonant converter of claim 14, wherein the first resonant circuit includes a first resonant resistor, a first transformer, and a first magnetizing inductor, the first transformer including a first primary winding and a first secondary winding, the first resonant resistor being connected between the first midpoint and a first end of the first primary winding, the first magnetizing inductor being connected in parallel with the first primary winding, and a first end of the first secondary winding being connected to the first sub-midpoint; the second resonant circuit includes a second resonant resistor, a second transformer, and a second magnetizing inductor, the second transformer including a second primary winding and a second secondary winding, the second resonant resistor being connected between the second midpoint and a first end of the second primary winding, the second magnetizing inductor being connected in parallel with the second primary winding, and a first end of the second secondary winding being connected to the second sub-midpoint; the third resonant circuit includes a third resonant resistor and a third transformer. The transformer includes a third primary winding and a third secondary winding. A third resonant resistor is connected between the third midpoint and a first end of the third primary winding. The third magnetizing inductor is connected in parallel with the third primary winding. A first end of the third secondary winding is connected to the third sub-midpoint. A second end of the first secondary winding, a second end of the second secondary winding, and a second end of the third secondary winding are connected to each other. The resonant circuit assembly further includes a fourth resonant resistor, a fifth resonant resistor, and a sixth resonant resistor. The fourth resonant resistor is connected between a second end of the second primary winding and a second end of the third primary winding. The fifth resonant resistor is connected between a second end of the first primary winding and a second end of the second primary winding. The sixth resonant resistor is connected between a second end of the first primary winding and a second end of the third primary winding.

17. The resonant converter of claim 1, wherein the first sub-circuit, the second sub-circuit, and the third sub-circuit are connected in parallel with each other.

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